Geographic Range
The distribution of
Eonycteris major
includes the Philippines through Borneo. In Borneo, there are scattered records
from most areas including Kota Kinabalu and Ranau in Sabah. It is also found in Gunung
Dulit and Kuching in Sarawak, Kutai in East Kalimantan, and upper Sungai Tengah in
South Kalimantan. The only area it is not found is in Central and West Kalimantan.
In the Philiippines, the distribution includes Biliran, Leyte, Lubang, Luzon, Maripipi,
Mindanao, Negros, and Siargao.
Habitat
The roosting habitat of
E. major
usually includes caves and hollow trees. The subspecies
E. m. robusta
may be dependent upon primary forest as well as caves and has been taken from near
sea level to 1100m.
- Habitat Regions
- tropical
- Terrestrial Biomes
- forest
- Other Habitat Features
- caves
Physical Description
The fur of
E. major
is identified as uniform and dark, blackish brown. Like most other fruit bats of
this genus, the muzzle is long, slender, and slightly decurved. The tongue is also
very long and slender, and protrudes from the mouth. Both characteristics help to
pick up nectar and pollen, the main source of food. The cheek teeth are reduced in
size. Overall, the bats from the subfamily
Macroglossinae
are characterized by long, needle-like canines, which are strongly curved outwards
in the lower jaw. The upper incisors are small and they project forward slightly and
are separated from each other by small gaps. The dental formula is unknown but the
dental formula for most
Macroglossinae
is 2/2, 1/1, 3/3, 2/3. The tail is usually very short, averaging 18 mm, and the ear
length averages 21 mm. The forearm (length outside of the elbow to the outside of
wrist in a bent wing) averages from 71 mm to 80 mm. Another distinguishing characteristic
is the lack of a claw on the second digit of the wing, which is usually present in
Pteropodidae
. Although there is no information about sexual dimorphism, the closest relative of
E. major
is
E. spelaea
, which is known to be sexually dimorphic; males are generally larger than females.
- Other Physical Features
- endothermic
- bilateral symmetry
Reproduction
There is little available information on mating systems in Eonycteris major .
There is no information about reproductive behavior in
E. major
but there is some information on its closest relative,
E. spelaea
. The females have been found to be polyestrous and pregnancies that begin during
later stages of lactation are successive. The gestation period is a little bit longer
than six months but can be as long as 200 days. Generally females have one young
per litter, and rarely two. The young are attached to the nipple for about 4 to 6
weeks and weaning occurs after 3 months. They reach sexual maturity after one year
in females and after two years in males.
- Key Reproductive Features
- gonochoric/gonochoristic/dioecious (sexes separate)
- sexual
- viviparous
There is little available information on the parental investment of
E. major
, but observations of their relative
E. spelaea
show that the young take hold of a nipple shortly after parturition. For 4 to 6
weeks, the young stay firmly attached as the female flies around. The young can make
short flights on their own after 4 to 6 weeks and weaning occurs three months later.
- Parental Investment
-
pre-weaning/fledging
-
provisioning
- female
-
protecting
- female
-
provisioning
Lifespan/Longevity
There is little available information on studies of the lifespan of this species either in the wild or in captivity.
Behavior
The subspecies
E. m. robusta
is known to be gregarious. Several hundred were found roosting in colonies that
were divided into groups, separated by sex. They are also known to share roosting
caves with
E. spelaea
and probably
Rousettus amplexicaudatus
.
Home Range
There is little available information on the home range of
E. major
. The nearest relative,
E. spelaea
, migrates long distances to its feeding grounds and in general, members of the family
Pteropodidae
are known to make long flights between their roosting and feeding areas.
Communication and Perception
There is little available information on the way this species communicates how it
perceives the environment. In general, members of the family
Pteropodidae
have large, well-developed eyes, and therefore perceive their environment visually.
Most species of this family are also known to locate their food by smell.
- Communication Channels
- visual
Food Habits
Not much is known about the specific plants
E. major
feeds on, but it is known that its natural foods appear to be mainly made up of pollen
and nectar.
- Primary Diet
- herbivore
- Plant Foods
- fruit
- nectar
- pollen
Predation
There is little available information on the predators of this species or the adaptations it has to avoid such predators.
Ecosystem Roles
They serve a role in the pollination of their host plants.
- Ecosystem Impact
- pollinates
Economic Importance for Humans: Positive
There is little available information on the benefits of this species to humans except as a pollinator.
Economic Importance for Humans: Negative
There are no known adverse effects of E. major on humans.
Conservation Status
This species is not threatened and there is no evidence of serious threats to the
population. On the other hand, its subspecies
E. m. robusta
is identified as rare. It is believed that this rarity may have been caused by deforestation,
because
E. major
is strongly association with primary forests. This species may be threatened but
it is difficult to know because it is so rare. It is believed that even without protection,
they will continue to survive with low numbers as long as there are undisturbed cave
roosts available.
Additional Links
Contributors
Matthew Wund (editor), University of Michigan-Ann Arbor.
Yan-Iuan Ho (author), University of Michigan-Ann Arbor, Phil Myers (editor, instructor), Museum of Zoology, University of Michigan-Ann Arbor.
- oriental
-
found in the oriental region of the world. In other words, India and southeast Asia.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
- tropical
-
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
- forest
-
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
- sexual
-
reproduction that includes combining the genetic contribution of two individuals, a male and a female
- viviparous
-
reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.
- nocturnal
-
active during the night
- motile
-
having the capacity to move from one place to another.
- colonial
-
used loosely to describe any group of organisms living together or in close proximity to each other - for example nesting shorebirds that live in large colonies. More specifically refers to a group of organisms in which members act as specialized subunits (a continuous, modular society) - as in clonal organisms.
- visual
-
uses sight to communicate
- visual
-
uses sight to communicate
- tactile
-
uses touch to communicate
- chemical
-
uses smells or other chemicals to communicate
- herbivore
-
An animal that eats mainly plants or parts of plants.
- nectarivore
-
an animal that mainly eats nectar from flowers
- endothermic
-
animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.
- bilateral symmetry
-
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
References
Altringham, J. 1996. Bats Biology and Behaviour . United States: Oxford University Press.
Mickleburgh, S., A. Hutson, P. Racey. 1992. Old World Fruit Bats . Gland, Switzerland: IUCN.
Nowak, R. 1994. Walker's Bats of the World . Baltimore and London: The Johns Hopkins University Press.
Payne, J., C. Francis. 1985. A Field Guide to the Mammals of Borneo . Kuala Lumpur: The Sabah Society.
2004. "Animal Diversity Web" (On-line). Accessed February 11, 2004 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Eonycteris_spelaea.html .